Working fluid cassette with hinged plenum or enclosure for interfacing heat exchanger with intravascular temperature management catheter

ABSTRACT

An enclosure or plenum that supports a looped pump tube is hingedly connected to a framed thin-walled heat exchange bag through which working fluid from an intravascular heat exchange catheter flows. The frame with bag can be inserted between cold plates to exchange heat with the working fluid flowing through the bag. With the framed bag between the plates, the looped pump tube from the enclosure or plenum is receivable in the raceway of a peristaltic pump, which pumps working fluid through the system.

TECHNICAL FIELD

The present application relates generally to heat exchange systems forpatient temperature control with working fluid cassettes.

BACKGROUND

Patient temperature control systems have been introduced to preventfever in patients in the neuro ICU due to suffering from sub-arachnoidhemorrhage or other neurologic malady such as stroke. Also, such systemshave been used to induce mild or moderate hypothermia to improve theoutcomes of patients suffering from such maladies as stroke, cardiacarrest, myocardial infarction, traumatic brain injury, and highintracranial pressure. Examples of intravascular heat exchange cathetersare disclosed in U.S. Pat. Nos. 7,914,564, 6,416,533, 6,409,747,6,405,080, 6,393,320, 6,368,304, 6,338,727, 6,299,599, 6,290,717,6,287,326, 6,165,207, 6,149,670, 6,146,411, 6,126,684, 6,306,161,6,264,679, 6,231,594, 6,149,676, 6,149,673, 6,110,168, 5,989,238,5,879,329, 5,837,003, 6,383,210, 6,379,378, 6,364,899, 6,325,818,6,312,452, 6,261,312, 6,254,626, 6,251,130, 6,251,129, 6,245,095,6,238,428, 6,235,048, 6,231,595, 6,224,624, 6,149,677, 6,096,068,6,042,559, 8,888,729, and USPPs 2013/0178923, 2013/0079855,2013/0079856, 2014/0094880, 2014/0094882, 2014/0094883, all of which areincorporated herein by reference.

External patient temperature control systems may be used. Such systemsare disclosed in U.S. Pat. Nos. 6,827,728, 6,818,012, 6,802,855,6,799,063, 6,764,391, 6,692,518, 6,669,715, 6,660,027, 6,648,905,6,645,232, 6,620,187, 6,461,379, 6,375,674, 6,197,045, and 6,188,930(collectively, “the external pad patents”), all of which areincorporated herein by reference.

In general, in all of the intravascular and external patient temperaturecontrol solutions, the temperature of the working fluid flowing throughthe catheter or pad is regulated by a heat exchange console based onfeedback provided by the patient's actual body temperature, typicallycore body temperature as may be variously measured rectally,esophageally, tympanic ear temperature, blood temperature in, e.g., thevena cava, etc. The working fluid temperature is regulated by thermallycoupling the working fluid to heating and/or cooling elements in theconsole. In many cases, the working fluid is forced in a closed fluidcircuit path (including the console and the catheter or pad) by aperistaltic pump acting on tubing, e.g., pump tubing or IV tubing, inthe fluid circuit path.

SUMMARY

The following patent applications are hereby incorporated by referenceherein in their entirety, Ser. No. 14/534,718, filed Nov. 6, 2014, andfiled concurrently herewith.

As understood herein, it is desirable to provide a fast and easy way tointerconnect an intravascular heat exchange catheter or external padwith a heat exchanger.

Accordingly, a device is provided which includes a thin-walled bagsupported by a frame. The bag with frame is receivable between heatexchange plates such that heat can be exchanged between working fluidflowing through the bag and at least one of the heat exchange plates. Aplenum or enclosure is connected to the frame. The plenum or enclosuresupports a pump tube in fluid communication with the bag. The pump tubemay be configured, for example in a loop, to engage a raceway or channelof a pump so that the pump can urge against the pump tube to circulateworking fluid.

The plenum or enclosure may be hingedly connected to the frame formovement between a shipping position, in which an open or closed bottomside of the plenum or enclosure is parallel to the frame and is closelyspaced from the bag, and an operating position, in which the bottom sideis perpendicular to the frame. In some examples, a return tube isconfigured for carrying working fluid from an intravascular heatexchange catheter or external heat exchange pad to the bag.

If desired, a reservoir may be in the plenum or enclosure, or be a partof the plenum or enclosure, for receiving working fluid from the bag. Inthis example, the pump tube can receive working fluid from thereservoir. Also, a damper or dampener tube may be in fluid communicationwith the pump tube for receiving working fluid from the pump tube. Thedampener tube may be configured with one or more pulse dampening loopsor may be a straight or substantially straight length tube. Stillfurther, a supply tube can be in fluid communication with the dampenertube for conveying working fluid to an intravascular heat exchangecatheter or external heat exchange pad. In certain embodiments, thedampener may be in a form other than a tube. The dampener may be anypulse dampener, e.g., a dampener tube, damper or other device thatabsorbs the shock caused by a change in the direction or the speed offluid flow within the tubes or other shock created by the pump's action.Other examples of dampeners include but are not limited to foam and airdampeners.

In some examples, working fluid from the return tube passes through anentry tube in a top rail of the frame to enter the bag. The entry tubehas a first diameter and terminates proximate to the top rail so thatworking fluid enters the bag proximate the top rail. A drain tubeextends through the entry tube toward a bottom rail of the frame that isopposite to and parallel with the top rail, with the drain tubeterminating in an opening proximate to or remaining close to the bottomrail. The drain tube can be used for emptying the bag by reversing thepump to withdraw working fluid from the bag through the drain tube.

In another aspect, a device includes a plenum or enclosure that supportsa looped pump tube, and a framed thin-walled heat exchange bag connectedto the plenum or enclosure. The thin-walled heat exchange bag is forholding working fluid from an intravascular heat exchange catheter orexternal heat exchange pad, and is configured for insertion betweenopposed plates to effect heat exchange between the plates and workingfluid flowing through the bag. When the framed thin-walled heat exchangebag is between the plates, the looped pump tube from the plenum orenclosure is receivable in or may be positioned in a raceway or channelof a peristaltic pump.

In another aspect, a method includes engaging a loop of a pump tubesupported by a plenum or enclosure with a raceway or channel of aperistaltic pump, and disposing a heat exchange bag that dependsdownwardly from the plenum or enclosure between opposed plates of a heatexchanger.

The details of the various embodiments described herein, both as totheir structure and operation, can best be understood in reference tothe accompanying drawings, in which like reference numerals refer tolike parts, and in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a non-limiting system in accordance withone embodiment;

FIG. 2 is an exploded perspective view of an example pump with cassette;

FIG. 3 is a perspective view of an example cassette with the plenum inthe shipping position;

FIG. 4 is a perspective view of an example cassette with the plenum inthe operating position;

FIG. 5 is a perspective view of an example cassette with the plenumhinged or rotated beyond the operating position;

FIG. 6 is a perspective view of the interior of the plenum as would beseen from the bottom of the plenum when disposed for operating;

FIG. 7 is a perspective view of the pump assembly with the rotor in aload position;

FIG. 8 is a perspective view of the pump assembly with the rotor in alock (operational) position;

FIG. 9 is a perspective view showing the cassette with pump assemblyhaving a rotor in the load position;

FIG. 10 is a perspective view showing the cassette with pump assemblyhaving a rotor in the lock (operational) position; and

FIG. 11 a perspective view of an example cassette embodiment showing adrain tube for the thin-walled heat exchange bag, with portions of theframe broken away for clarity and with the plenum removed for ease ofdisclosure.

DETAILED DESCRIPTION

Referring initially to FIG. 1 , in accordance with present principles, asystem 10 may include an intravascular heat exchange catheter 12controlled by a control system 14 to control patient temperature, e.g.,to prevent the patient 16 from becoming febrile or to induce therapeutichypothermia in the patient 16. In the catheter, working fluid or acoolant such as but not limited to saline circulates (typically underthe influence of a pump “P” in the control system) in a closed loop fromthe control system 14, through a fluid supply line L1, through thecatheter 12, and back to the system 14 through a fluid return line L2,such that no working fluid or coolant enters the body. While certainpreferred catheters are disclosed herein, it is to be understood thatother catheters can be used in accordance with present principles,including, without limitation, any of the catheters disclosed above orin the following U.S. patents, all incorporated herein by reference:U.S. Pat. Nos. 6,419,643, 6,416,533, 6,409,747, 6,405,080, 6,393,320,6,368,304, 6,338,727, 6,299,599, 6,290,717, 6,287,326, 6,165,207,6,149,670, 6,146,411, 6,126,684, 6,306,161, 6,264,679, 6,231,594,6,149,676, 6,149.673, 6,110,168, 5,989,238, 5,879,329, 5,837,003,6,383,210, 6,379,378, 6,364,899, 6,325,818, 6,312,452, 6,261,312,6,254,626, 6,251,130, 6,251,129, 6,245,095, 6,238,428, 6,235,048,6,231,595, 6,224,624, 6,149,677, 6,096,068, 6,042,559, 8,888,729,5,486,208, 5,837,003, 6,110,168, 6,149,673, 6,149,676, 6,231,594,6,264,679, 6,306,161, 6,235,048, 6,238,428, 6,245,095, 6,251,129,6,409,747, 6,368,304, 6,338,727, 6,299,599, 6,287,326, 6,126,684,7,211,106 and USPPs 2013/0178923, 2013/0079855, 2013/0079856,2014/0094880, 2014/0094882, 2014/0094883, all of which are incorporatedherein by reference. The catheter 12 may be placed in the venous system,e.g., in the superior or inferior vena cava.

Instead of or in addition to the catheter 12, the system 10 may includeone or more pads 18 that are positioned against the external skin of thepatient 16 (only one pad 18 shown for clarity). The pad 18 may be,without limitation, any one of the pads disclosed in the external padpatents. The temperature of the pad 18 can be controlled by the controlsystem 14 to exchange heat with the patient 16, including to inducetherapeutic mild or moderate hypothermia in the patient in response tothe patient presenting with, e.g., cardiac arrest, myocardialinfarction, stroke, high intracranial pressure, traumatic brain injury,or other malady the effects of which can be ameliorated by hypothermia.The pad 18 may receive working fluid from the system 14 through a fluidsupply line L3, and return working fluid to the system 14 through afluid return line L4. The pump “P” may be a peristaltic pump which mayengage any one of the lines L1-L4, which are typically plastic or othermaterial IV lines, to urge working fluid through the lines throughperistalsis.

The control system 14 may include one or more microprocessors 20receiving target and patient temperatures as input and controlling,among other things, the pump “P” and a refrigerant compressor 22 and/ora bypass valve 24 that can be opened to permit refrigerant to bypass acondenser.

Turning now to FIG. 2 , an example of the pump “P” in FIG. 1 is shownand generally designated 30. It is to be understood that the pumpassembly shown in FIG. 2 is coupled to cold plates 31 (shownschematically in FIG. 2 ) between which the below-described heatexchange or cassette bag is positioned to exchange heat with workingfluid flowing through the bag to and from the catheter 12 or pad 18.Example details of the interplay between the cassette bag and coldplates are disclosed in U.S. patent application Ser. No. 14/180,719,filed Feb. 14, 2014, incorporated herein by reference.

The pump 30 includes a rigid, preferably metal or hard plastic racewayor channel housing 32 and a rotor 34. The raceway housing 32 may beformed from one or more blocks of material as shown and has an innerarcuate surface 36 which may have a substantially constant radius ofcurvature. In some examples, the arcuate surface 36, which defines amidpoint 38 between its two ends, can extend through an arc of at leastone hundred eighty degrees (180°) (e.g., where two drive rollers areused) and may extend through an arc of between one hundred eightydegrees (180°) and two hundred seventy degrees (270°). In the exampleshown, the arcuate surface 36 extends, from one end to the other end,through an arc of greater than 200°. For example, the arc may be about210° to 230°. In certain embodiments, the arcuate surface of a racewaymay extend through an arc equal to 360° divided by n, where n is equalto the number of drive rollers mounted on or near a rotor which isrotated relative to the raceway.

A motor 40 rotates the rotor 34 relative to the raceway 32. As well, therotor 34 is movable translationally and/or rotationally relative to theraceway 32 as shown by the arrows 42 between a pump position, in whichthe rotor 34 is spaced from the midpoint 38 of the inner surface 36 ofthe raceway 32 a first distance, and a tube load position, in which therotor 34 is spaced from the midpoint 38 a greater, second distance. Inthe pump or operating position, rollers on the rotor 34 urge against atube such as an IV tube that is disposed between the rollers and theraceway 32. In the tube load position, the rotor 34 is sufficientlyspaced from the raceway 32 to permit a tube 44 to be disposed betweenthe raceway and rotor and to be removed therefrom, e.g., by hand. Therotor 34 may be moved translationally and/or rotationally by, e.g., anactuator stepper motor, or by a manually-actuated lever linkage, orother appropriate mechanism or means.

Mounted on the rotor 34 are one or more rollers to urge against the tube44 to pump fluid through the tube. In the example shown in FIG. 2 , therotor 34 is defined in part by a rectilinear, non-square body, and on ornear each corner of the body a roller is mounted, e.g., rotatablymounted to the rotor body. In the example, at one set of opposed cornerson the body, drive rollers 46 are respectively mounted (only one driveroller shown in the perspective of FIG. 2 ), whereas at the other set ofopposed corners on the body, guide rollers 48 are respectively mounted.Thus, between the drive rollers 46 are guide rollers 48.

As shown in FIG. 2 , the drive roller 46 has a cylindrical outersurface, and at least a portion of the outer surface is configured tourge against the tube 44. The outer surface of the example drive rollermay be a single smooth cylinder and/or it may or may not have one ormore flanges having peripheries extending beyond the cylindrical outersurface. In contrast, the guide roller 48 also has a cylindrical outersurface but in addition includes top and/or bottom flanges definingrespective peripheries extending beyond the cylindrical outer surface ofthe guide roller such that the tube 44 can be received on thecylindrical outer surface of the guide roller between the flanges whenthe rotor 34 is in the pump position and is rotated. In the exampleshown, two and only two drive rollers 46 and two and only two guiderollers 48 are provided, but any number of drive and/or guide rollersmay be utilized. In certain embodiments, the drive roller or guideroller may have a non-cylindrical or partially cylindrical outersurface.

The tube 44 may be configured as a loop, with the ends of the loopengaged with a plenum 50 (while certain embodiments below refer to aplenum, an enclosure, compartment or other like component may beutilized) of a working fluid cassette, generally designated 52. Theplenum 50 is hingedly engaged with or coupled to a framed cassette bag54. Example details of the framed bag 54 are discussed further below.Additional example details that may be used with the working fluidcassette 52 are shown and described in U.S. patent application Ser. Nos.14/180,613 and 14/180,655, filed Feb. 24, 2014 and incorporated hereinby reference. Such a cassette can be engaged with structure in thecontrol system 14 to exchange heat with working fluid flowing throughthe cassette 52 and tube 44 and being circulated by the pump 30 shownand described herein to and from a heat exchange member such as thecatheter 12 and/or pad 18 through, e.g., the lines L1 and L2 shown inFIG. 1 . Note that the plenum 50 may also be connected via an IV line toan external working fluid reservoir such as an IV bag 57.

When the bag 54 is disposed vertically between the cold plates 31 asdescribed in the above-referenced U.S. patent application Ser. No.14/180,719, the plenum 50 can be locked into place as the rotor of thepump 30 moves into the pump or operating position as described furtherbelow.

In examples, the cassette bag 54 may be made of two polymeric membranesclosely spaced from each other and supported by a frame that is slidablyengageable with a slot 56 on a cold plate assembly that supports thepump of FIG. 2 . In certain embodiments, the frame may be made in halvesthat are positioned to sandwich or securely support a border portion ofthe cassette bag 54 therebetween. In certain variations, the cold plateassembly may include receptacles for receiving a portion of the cassetteas it is inserted into the slot 56. The receptacles may be keyed or eachreceptacle may have a different shape which corresponds to the shapes orconfiguration of a portion the cassette or cassette frame received bythe receptacles. These features would help ensure that the cassette isinserted between the cold plates in the correct or proper orientation,providing guidance to a user. A working fluid chamber is establishedbetween the membranes. In one example, each membrane is no more thanthree mils (0.003″) thick and may be between one mil and three mils inthickness (0.001→-0.003″), inclusive. In certain embodiments, eachmembrane may be between one mil and five mils in thickness(0.001″-0.005″). The example preferred membranes are more or lesssquare, with the length of top and bottom edges of the example membranesbeing approximately equal (within ±10% and more preferably within ±5%)of the lengths of the left and right edges of the membranes. Thus, theworking fluid chamber between the membranes may also be rectilinear andthere may be no obstructions between the membranes, meaning the Workingfluid chamber is a complete rectilinear, more or less square chamber. Inpreferred examples, the membranes are stretched under tension duringassembly to the frame.

FIGS. 3 and 4 show that the cassette bag 54 is bounded by a frame 60,and that the plenum 50 is joined to the frame 60 at a hinge 62 formovement between a shipping position (FIG. 3 ), in which an open bottomside 64 of the plenum 50 is parallel to the frame 60 and is closelyspaced from the bag 54, and an operating position (FIG. 4 ), in whichthe open bottom side 64 is rotated 90° from the shipping position sothat it is perpendicular or close to perpendicular to the frame 60. Ahinged plenum or enclosure 50 provides several advantages and benefits.For example, it allows the cassette to easily assume a more compactshipping configuration or operating position. Positioning the plenum orenclosure perpendicular to or angled relative to the frame provides foran increased angular tolerance between the cassette and the pump whenthe cassette is positioned within the cold plates and coupled to thepump. Also, the perpendicular or angled configuration allows a user tohave top view of the pump and the cold plate simultaneously when thecassette is positioned in between the cold plates and the tube 44 iscoupled to the pump. While the bottom side 64 of the plenum or enclosureis shown as having an open configuration, in certain embodiments, thebottom, side may be closed or at least a portion of the bottom side maybe closed. The bottom side 64 is generally rectangular and extends thewidth of the frame 60 as shown. In some examples the plenum 50 orenclosure may be pivoted or rotated beyond the operating position toestablish an obtuse angle with respect to the frame 60 as shown in FIG.5 . As shown best in FIG. 3 , the bottom side 64 is opposed by acomplementarily-shaped closed or open top side 66 and is spacedtherefrom by sidewalls 68.

FIG. 6 shows the interior of an open bottom side 64 of the plenum 50. Areturn tube 70 carrying working fluid from the catheter 12 or heatexchange pad 18 enters one of the sides 68 of the plenum 50. The returntube 70 passes across the plenum 50 to the opposite side, where it issupported by a support or bearing 72, entering an inlet opening 74 of atop rail 76. The return tube 70 ends, as further discussed below inreference to FIG. 11 , just below the top rail 76 in the bag 54. Workingfluid flows out of the return tube and into the bag 54 as indicated bythe arrow 78, back across the bag, and out of an exit tube 80 thatextends through an opening in the top rail 76.

The exit tube 80 in turn enters an enclosed working fluid reservoir 84in the plenum 50, e.g., through an entry port connector 86. Thereservoir may be a separate container or manifold positioned within theenclosure or plenum or may be integral with the enclosure or plenum. Thereservoir may collect or hold an amount of working fluid necessary orrequired to run the system. One or more level sensors may be provided inthe reservoir 84 to generate a signal when the reservoir fluid levelfalls below a threshold. The signal can be used to activate a warninglamp or audio alarm. Note that the entry port connector 86 is locatednear the top of the reservoir 84 in the bottom view shown. Also, an IVbag line or tube 87 is connected to the reservoir 84 via an IV bagconnector 88 to supply working fluid to the system from the IV bag 57shown in FIG. 2 . While the embodiments refer to an IV bag, other IV orworking fluid sources may be used, e.g., a bottle, bag or othercontainer. The reservoir 84 may be connected to the IV bag through asingle line 87 used to deliver working fluid to the reservoir 84, e.g.,during priming of the system and/or to compensate for thermal and otherfluctuations of the working fluid's volume. The line 87 may also be usedto evacuate air from the system and into the IV bag, and/or to bring theworking fluid back into the IV bag during purging or draining of thesystem at the end of a procedure.

A single line or tube 87 in a closed fluid circuit path provides asterile barrier or environment for the working fluid and also providesenhanced or improved convenience. Working fluid, e.g., saline, may bedelivered through the line 87, and air may travel back up through thesame line 87, in an opposite direction if desired, e.g., during priming,allowing for the delivery of two different fluids (e.g., water or salineand air) through the same line. The delivery of saline and air may notoccur simultaneously and/or a filter may not be required. A closed fluidcircuit path or closed loop system utilizing a single IV bag line orother fluid source line without a filter may work for up to 7 days, andin certain embodiments may work for more than 7 days. The pump describedherein may operate in both directions, and the pump may be self-primingsuch that it can pump air and/or water.

Near the bottom of the reservoir 84, an outlet connector 90 establishesfluid communication between the working fluid in the reservoir 84 andthe peristaltic tube 44 which extends through a tube exit opening 92 toengage the peristaltic pomp described above. The pump urges against thetube 44 to circulate working fluid in the pathway described herein. Thetube 44 reenters the plenum 50 through a tube entry opening 94 to engageor be made integrally with a dampener tube 96. The tube 44 may connectto a downstream dampener or dampener tube directly or via anintermediate tribe or manifold.

As shown, the example dampener tube 96 has a larger diameter than theexit tube 80 and furthermore extends back and forth across the plenum 50one or more or multiple times, e.g., being bent through one or more 180degree loops as shown. Alternatively, the dampener tube may be partiallyor entirely located outside of the plenum, and or may be a straight orsubstantially straight length tube with no or minimal loops. The purposeof the dampener tube 96 is to dampen pulses in the working fluid causedby the peristaltic pumping action. The dampener tube 96 is joined to asmaller diameter working fluid supply tube 98 at a clamp-like joint 100.Working fluid is conveyed to the catheter 12 or pad 18 through thesupply tube 98.

FIGS. 7-10 illustrate an example interlock that may be provided betweenthe pump 30 and the cassette 52. FIGS. 7 and 9 illustrate the pompassembly with the rotor 34 in the loading configuration or position andFIGS. 8 and 10 show the pump assembly with the rotor 34 in the lock(operating or pump) configuration or position.

In FIGS. 7 and 9 , a horizontal locking bar 120 terminating in anupwardly-projecting engagement hook 122 is connected to a rotor carriageor motor mount, which supports the rotor 34, so that the locking bar 120moves in the directions indicated by the arrows 124 as the rotorcarriage or mount and rotor move as described in reference to FIG. 2 .The rotor carriage or mount (and hence locking bar 120) are in the loadposition in FIGS. 7 and 9 , in which the rotor 34 is distanced from theraceway or raceway surface 36 to allow the pump tube 44 of the cassette52 to be engaged or placed in the space between the rotor 34 and theraceway. As shown in FIG. 9 , an engagement shelf 126 or protrusion onthe bottom of the cassette 52 is clear of the engagement hook 122 inthis position, allowing the cassette 52 to be moved to position the pumptube 44 in the raceway 32.

In contrast, FIGS. 8 and 10 show that when the rotor carriage or mountand rotor 34 are moved to the lock, pump or operating position such thatthe pump rollers can urge the pump tube 44 against the raceway orraceway surface 36, the locking bar 120 also moves to a position inwhich the engagement hook 122 has moved onto the top surface of theengagement shelf 126, trapping the shelf 126 and, hence, the cassette 52so that the cassette 52 cannot be withdrawn when in the rotor carriageor mount, the rotor, and the locking bar 120 with hook 122 are in thelock, pump or operating position.

FIG. 11 illustrates that in some examples, working fluid from the returntube 70 in FIG. 6 passes through the plenum 50 or enclosure (not shownin FIG. 11 ) to an entry tube 130 (which may be the same as or connectedto the return tube). The entry tube 130 passes into an opening 132 in atop rail 134 of the cassette frame 60 to enter the bag 54. In theexample shown, the entry tube 130 terminates in or just below (e.g., ¼→below) the top rail 134 so that working fluid exists the entry tube 130proximate to the top rail 134 and flows downwardly and across the bag54.

A drain tube 138 with a smaller diameter than the entry tube 130 extendsthrough the entry tube 130 as shown toward a bottom rail 140 of theframe 60 that is opposite to and parallel with the top rail 134. Thedrain tube 138 terminates in an opening 142 that is proximate to (e.g.,within ¼→ or so of) the bottom rail 140. When working fluid is beingcirculated through the catheter 12 and bag 54 during patient temperaturemanagement operation, at least a portion of the working fluid beingreturned from the catheter 12 to the cassette 52 exits the largerdiameter opening of the entry tube 130, near the top of the cassette 52,and at least a portion of the working fluid flows down and across thebag 54 to exchange heat with the plates between which the bag 54 isdisposed.

When it is desired to drain the catheter and/or bag to facilitatewithdrawal of the bag 54 from the plates, which can be impeded if thebag 54 remains full of working fluid, the pump may be reversed. Thisevacuates working fluid from bag 54 through the drain tube 138. Theevacuation causes the bag material to collapse around the larger entrytube 130, leaving most of the suction at the opening 142 of the draintube 138. The working fluid is pumped through the drain tube 138 backinto the reservoir 84 in the plenum or enclosure and from there to theIV bag. When the catheter remains connected to the cassette 52, workingfluid is also evacuated from the catheter. When the catheter is notconnected prior to draining the bag 54, the connectors (typically Luerfittings) that connect catheter IV lines to the supply and return linesof the cassette may be simply connected together to close the fluidloop.

In certain embodiments, a check valve 81 (FIG. 6 ) may be placed on orin the line or tube between the heat exchange bag 54 and the reservoir84 to prevent working fluid from moving from the reservoir 84 back tothe heat exchange bag 54 during fluid evacuation or purging. Optionally,a check valve 81 may be placed inside the reservoir 84 to preventworking fluid from moving from the reservoir 84 back to the heatexchange bag 54 during fluid evacuation or purging. Such valves mayensure that the working fluid is evacuated and/or flows back to an IVbag or other container, such that the heat exchange bag may be properlydrained and may be easily removed from between the heat exchange plates.Working fluid may also be evacuated or drained from the catheter, whenthe catheter is connected to the system, which results in a reduction inthe diameter of the catheter such that the catheter may be removed froma patient. If desired, the catheter may be disconnected, such that onlythe heat exchange bag is drained or evacuated of working fluid. In otherembodiments, a high pressure dampener may be utilized that providesfluctuations in the volume of working fluid, such that purging ordraining of working fluid may be performed with or without a checkvalve.

In certain embodiments, when filling the cassette bag during priming,the pump can be started and stopped in short periods to allow air tovent back through the reservoir in the plenum or enclosure. The pump mayalso be reversed to speed up the movement of air back through thereservoir and/or to the IV bag or fluid source. A single line may beused for delivering liquid and/or air between the reservoir and the IVbag or fluid source, allowing air to be removed from the fluid pathwithout requiring the use of either a two-lumened spike line which maybe more difficult for the user to install, or a hydrophobic vent orother filter which allows air to escape but may break down over timecausing working fluid to leak out of the system.

Components included in one embodiment can be used in other embodimentsin any appropriate combination. For example, any of the variouscomponents described herein and/or depicted in the Figures may becombined, interchanged or excluded from other embodiments. “A systemhaving at least one of A, B, and C” (likewise “a system having at leastone of A, B, or C” and “a system having at least one of A, B, C”)includes systems that have A alone, B alone, C alone, A and B together,A and C together, B and C together, and/or A, B, and C together, etc.

While various embodiments of a WORKING FLUID CASSETTE WITH HINGED PLENUMOR ENCLOSURE FOR INTERFACING HEAT EXCHANGER WITH INTRAVASCULARTEMPERATURE MANAGEMENT CATHETER are herein shown and described indetail, the scope of the present invention is to be limited by nothingother than the appended claims.

What is claimed is:
 1. A device, comprising: a bag supported by a frame,the bag with frame being receivable between heat exchange plates suchthat heat can be exchanged between working fluid flowing through the bagand at least one of the heat exchange plates, wherein the frame includesfirst and second halves that support a border portion of the bagtherebetween; and a plenum supporting a conduit in fluid communicationwith the bag, the conduit being configured to extend exteriorly of theplenum to engage a pump so that the pump can urge against the conduit tocirculate working fluid, wherein working fluid from a heat exchangeelement is passable through an entry tube in a first rail of the frameto enter the bag, the entry tube having a first diameter and terminatingproximate to the first rail so that working fluid enters the bagproximate the first rail, and the device further comprises a drain tubeextending toward a second rail of the frame that is opposite to andparallel with the first rail, the drain tube terminating proximate tothe second rail, the drain tube being useful for emptying the bag byreversing the pump to withdraw working fluid from the bag through thedrain tube, wherein the plenum is rotatably coupled to the frame formoving between a shipping position and an operating position, in whichthe plenum moves from a first configuration for the shipping position toa second configuration for the operating position.
 2. The device ofclaim 1, wherein the plenum is hingedly connected to the frame formovement between the shipping position, in which the first configurationcomprises an open bottom side of the plenum being parallel to the frameand is closely spaced from the bag, and the operating position, in whichthe second configuration comprises the open bottom side beingperpendicular to the frame.
 3. The device of claim 1, comprising areturn tube configured for carrying working fluid from a heat exchangecatheter or external heat exchange pad to the bag.
 4. The device ofclaim 3, comprising a reservoir in the plenum for receiving workingfluid from the bag.
 5. The device of claim 4, wherein the conduit isconfigured to receive working fluid from the reservoir.
 6. The device ofclaim 1, comprising a dampener tube in fluid communication with theconduit for receiving working fluid from the conduit, the dampener tubebeing configured to dampen pulses in the working fluid.
 7. The device ofclaim 6, wherein the dampener tube is configured with one or moredampening loops.
 8. The device of claim 6, comprising a supply tube influid communication with the dampener tube for conveying working fluidto an intravascular heat exchange catheter or external heat exchangepad.
 9. The device of claim 1, wherein the drain tube extends throughthe entry tube.
 10. The device of claim 1, wherein the conduit supportedby the plenum is in a superposed relation to the bag when the plenum isin the shipping position.
 11. A device comprising: an enclosure in whichis disposed a pump tube; an assembly comprising a heat exchange bagcoupled to the enclosure, the heat exchange bag for holding workingfluid from an intravascular heat exchange catheter or external heatexchange pad, the heat exchange bag being configured for insertionbetween opposed plates to effect heat exchange between the opposedplates and working fluid flowing through the heat exchange bag, whereinwhen the heat exchange bag is between the opposed plates, the pump tubefrom the enclosure is receivable in a peristaltic pump, wherein workingfluid from the intravascular heat exchange catheter or external heatexchange pad is configured to pass through an entry tube to enter theheat exchange bag; and a dampener tube in fluid communication with thepump tube for receiving working fluid from the pump tube, the dampenertube being configured to dampen pulses in the working fluid, wherein theenclosure is rotatably coupled to the assembly for movement between ashipping position and an operating position, in which the enclosuremoves from a first configuration for the shipping position to a secondconfiguration for the operating position, wherein at least a portion ofthe dampener tube extends exteriorly of the enclosure.
 12. The device ofclaim 11, wherein the enclosure is hingedly connected to the assemblyfor movement between the shipping position, in which the firstconfiguration comprises an open bottom side of the enclosure beingparallel to the assembly and being closely spaced from the heat exchangebag, and an operating position, in which the second configurationcomprises open bottom side being perpendicular to the assembly.
 13. Thedevice of claim 11, comprising a reservoir in the enclosure forreceiving working fluid from the heat exchange bag.
 14. The device ofclaim 13, wherein the reservoir is in fluid communication with an IVfluid source via a single IV line, and wherein the device provides aclosed fluid circuit path where liquid and air are configured to flow inopposite directions through the single IV line or other line.
 15. Thedevice of claim 11, wherein the pump tube is in fluid communication witha reservoir in the enclosure to receive working fluid from thereservoir.
 16. The device of claim 11, comprising: a drain tubeextending toward a rail of the assembly that is distanced from the entrytube, the drain tube being useful for emptying the heat exchange bag byreversing the peristaltic pump to withdrawn working fluid from the heatexchange bag through the drain tube.
 17. The device of claim 16, whereinthe dampener tube is configured with one or more pulse dampening loops.18. The device of claim 11, comprising a supply tube in fluidcommunication with the dampener tube for conveying working fluid to anintravascular heat exchange catheter or external heat exchange pad. 19.A device, comprising: a bag supported by a frame, the bag with framebeing receivable between heat exchange plates such that heat can beexchanged between working fluid flowing though the bag and at least oneof the heat exchange plates; and a plenum hingedly coupled to the frameand supporting a conduit in fluid communication with the bag, theconduit being configured to engage a pump so that the pump can urgeagainst the conduit to circulate working fluid, wherein working fluidfrom a heat exchange element is passable through an entry tube in afirst rail of the frame to enter the bag, the entry tube having a firstdiameter and terminating proximate to the first rail so that workingfluid enters the bag proximate the first rail.
 20. The device of claim19, comprising: a dampener tube in fluid communication with the conduitfor receiving working fluid from the conduit, the dampener tube beingconfigured to dampen pulses in the working fluid.